The San Joaquin Valley continues to face many air quality challenges as it strives to meet federal air quality standards for PM2.5 (fine particulate matter) and ground-level ozone. While there are many sources of air pollution in the Valley, residential wood burning and pollution from yard care equipment have a direct impact on neighborhoods.

Residential wood burning is the largest single source of particulate matter pollution in the Valley during winter months. For this reason, the District's residential wood smoke reduction program imposes restrictions on the use of fireplaces, wood stoves, fire pits and chimneys. The District recommends using other methods to heat your home unless wood burning is your sole source of heat. For full details on the District's Residential Wood Smoke Reduction Program, visit www.valleyair.org/rule4901.

The District also offers incentives for Valley residents to upgrade from wood burning devices to natural gas. Get all the information on the Burn Cleaner Incentive program here: www.valleyair.org/burncleaner.

Another source of air pollution are small engines on gas-powered yard care equipment, which have no emission controls. One gas-powered lawn mower can pollute as much as 12 late-model cars.

For every gas-powered lawn or garden tool, there is an electric or manual alternative that works just as well.

The District's Clean Green Yard Machines yard care incentive program provides significant rebates on electric lawn mowers, trimmers, edgers, pole saws and chain saws. For details on these incentives visit www.valleyair.org/cgym.

In addition, the Valley Air District suggests using a rake or broom instead of a blower. Leaf blowers create particulate matter in the form of dust and can be a nuisance to your neighbors.

Anthony Presto is the Outreach & Communications Representative for the San Joaquin Valley Air Pollution Control District

 

 

 

 [From the UC IPM blog Pests in the Urban Landscape] 

Citrus trees need care throughout the year, including cultural practices to keep trees healthy and pest management. During the fall season, several pests can attack citrus trees in many California regions. 

Brown Rot

Monitor for this disease by checking for damaged fruit on your tree, as well as fruit in storage. Sometimes affected fruit develops a pungent odor and can ruin fruit held in storage. See the UC IPM web page on Brown Rot to learn more.

Citrus Leafminer

If you see what look like small “tunnels” on your citrus tree leaves, your tree might have citrus leafminer. The adult stage of this pest is a small, light colored moth; the larval stage feeds and develops inside the leaves of young citrus and other closely related plants.

Citrus leafminer rarely causes problems for mature trees, however, it can seriously damage very young trees. Read the UC IPM Pest Notes: Citrus Leafminer for recommendations for prevention or management.

Snails and Slugs

Snails and slugs are attracted to citrus trees and can feed on foliage and fruit. A good sign that these pests are the perpetrators of tree damage are the silvery trails of slime along the ground or on tree leaves, or even see the snails or slugs themselves. For management tips, read the UC IPM Pest Notes: Snails and Slugs.

Asian Citrus Psyllid and Huanglongbing

You may have heard of the Asian citrus psyllid (ACP) and the deadly disease huanglongbing (also called citrus greening) that has been featured in the news. This disease doesn't pose a threat to humans or animals, but is deadly to citrus trees. Once a tree develops huanglongbing, there is no cure, so for this disease prevention is key.

Stopping this serious citrus pest will require everyone's help. To learn more about the psyllid and the disease, as well as what you can do, visit the UC IPM Pest Notes: Asian Citrus Psyllid and Huanglongbing Disease.

UC IPM Web Site

For information on managing other citrus pests in the garden, see the UC IPM webpage on Pests in Gardens and Landscapes: Citrus.

Light is probably the most important factor for indoor plant growth. In most houses, it's probably the most limiting factor as well. To add to the problem, light levels begin to dwindle in fall as the days become shorter. This means you may need to make some adjustments in the arrangement of your indoor plants during fall and winter.

When thinking about light levels for indoor plants, consider light intensity, duration and quality. Light intensity influences the manufacture of plant food, stem length, leaf color and flowering. For example, a plant that needs bright light that is grown in low light tends to be spindly with light green leaves. A similar plant grown in bright light would generally be shorter, better branched and have longer, darker green leaves.

The distance the plant is from the light source and the direction the windows in a home face determine the light intensity a houseplant receives. Southern exposures have the most intense light. Western and eastern exposures receive about 60 percent of the intensity of southern exposures, while northern exposures get only 20 percent of the light of southern exposures. Light intensity is also affected by the presence and type of curtains, the weather, shade from buildings or trees, the cleanliness of the windows and the reflectiveness of the surroundings.

When a plant gets too much direct light, the leaves become pale, sometimes sunburn, turn brown and die. During the summer, houseplants need to be protected from too much direct sunlight.

Ivy plants, philodendrons, foliage begonias and peperomias - grown mainly for their foliage - do well in indirect bright light. Tender plants, such as African violets, also should receive indirect light during the summer when the sun's rays are extremely intense.

Flowering plants require higher light levels for the development of good flowers. These plants grow best where they receive direct sunlight for at least half a day. Placing them near windows with an eastern exposure usually suits them best.

Here are some suggestions of houseplants for various light situations taken from the UC Master Gardener Handbook.

Low Light Plants

Common Name	Botanical Name
Corn Plant	Dracaena fragrans
Parlor Palm	Chamaedora elegans
Pothos*	Epipremnum aureum
Snake Plant	Sansevieria trifasciata

  Medium Light Plants 

Spider plant. (pxfuel.com)

Common Name	Botanical Name
Peperomia (species)	Peperomia or Pellionia
Rubber Plant	Ficus elastica
Schefflera	Schefflera actinophylla
Swedish Ivy/Creeping Charlie	Plectranthus australis

Bright Light

Common Name	Botanical Name
Christmas Cactus	Schlumbergia bridgesii
Spider Plant	Chlorophytum comosum
String of Hearts	Ceropegia woodii
Zebra Plant	Aphelandra squarrosa

*These plants are poisonous, keep away from kids and pets.

Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.

 

 

The Autumn Equinox signals a time of change in the seasons. The weather becomes cooler, the days shorter, skies turn a softer blue with occasional clouds, summer vegetable gardens are finishing up, and deciduous trees change colors and drop their leaves. By mid-November our neighborhoods and gardens will be littered with fallen leaves.

People often rake their leaves and put them out to be picked up as trash. I have always preferred to leave the leaves for my garden.

If you take a walk in a forest, you'll see leaf layers several inches deep around trees and bushes. Fallen leaves have a complex relationship with trees and nature, providing many benefits which can be reproduced to some extent in our gardens.

Natural Mulch

Leaf litter prevents rainwater and wind from carrying the soil's nutrients away. Water trickling through the leaf layer carries essential nutrients such as carbon, phosphorus, nitrogen, and other inorganic compounds, thus replenishing the soil.

Fallen leaves have the same weed suppression and moisture retention properties of shredded wood mulch—and they're free! Where mulch is desired as a decorative element, what could be more seasonally appropriate than a pile of brightly colored fall leaves? This natural mulch also provides insulating winter cover from cold temperatures for roots, seeds, and bulbs.

A Web of Life in Leaf Litter

Leaf litter isn't just free fertilizer and mulch. It provides food and shelter for a wide variety of living things including spiders, snails, worms, beetles, millipedes, mites, toads, frogs and more—these in turn support mammals, birds, reptiles, and amphibians that rely on these creatures for food.

Detritivores (organisms that eat dead or decaying plants or animals) break up and excrete leaf litter. Fungi and bacteria then take over and complete the recycling process converting these smaller pieces into nutrients which then sustain neighboring plants. They in turn help support biodiversity by becoming food themselves.

Some creatures use leaf litter and other dead vegetation to insulate themselves from winter's chill, while others, such as earthworms, feed on the litter, breaking it into smaller pieces.

Numerous bird species such as robins and towhees forage in the leaf layer searching for insects and other invertebrates to eat. 

Raking up leaves and putting them in the trash could have the unintended consequence of removing some of next year's garden butterflies and moths, many of which are pollinators. Most butterflies and moths overwinter in the landscape as an egg, caterpillar, chrysalis, or adult. In all but the warmest climates, they often use leaf litter for winter cover. Fritillaries and wooly bear caterpillars will tuck themselves into a pile of leaves for protection from cold weather and predators. Some Hairstreaks lay their eggs on fallen oak leaves, which become the first food of the caterpillars when they emerge. Swallowtail butterflies disguise their cocoons and chrysalises as dried leaves, blending in with the “real” leaves.

Bumble bees also rely on leaf litter for protection. At the end of summer, mated queen bumble bees burrow an inch or two into the earth to hibernate for winter. An extra thick layer of leaves is welcome protection from the elements.

All of which makes leaf litter an integral part of a complex web of life.

What You Can Do

Leaving the leaves where they are is ideal but isn't always practical for gardeners. If you have lawn, you can mulch the leaves with your mower, rake them up, and place them back in the garden around trees, shrubs, and plants. Spreading some of the chopped leaves around on your lawn will also nourish it. If possible, leave some leaves undisturbed in planters since shredded leaves will not provide the same cover as leaving them whole, and you may be destroying eggs, caterpillars, chrysalis, and other micro-creatures along with the chopped leaves.

Composting leaves is a terrific way to recycle and create a nutrient-rich garden soil amendment at the same time. Some gardeners opt for shredding their fall leaves for use in compost piles. Like people who mulch their lawn leaves with a mower, consider leaving some leaves undisturbed in garden beds and lawn edges. If space allows, you could create a leaf pile, allowing it to break down naturally, or add the leaves gradually to your compost pile over time. Such efforts will keep leaf litter critters safe and allow you to benefit from the rich garden gift that falls from the trees above.

While it is ideal to “leave the leaves” permanently—for the benefits mentioned above—if you do decide you need to clean your garden and remove the leaves in spring, try to wait until later in the season, so as to give the critters that have been protected by fallen leaves over the winter time to emerge and depart.

Some gardeners may be concerned that autumn leaves, matted down by rain or snow, could have a negative impact on their perennials. However, a thick layer of leaves provides additional insulation against chilly weather and protects newly planted perennials from frost which could damage tender roots and shoots. Anyone who has spotted fragile spring seedlings popping up in the woods knows that all but the most fragile of plants will erupt through the leaf litter in spring without trouble.

So, leave the leaves. While you can't perfectly emulate a forest, your garden will be healthier and more diversified, you'll help support a vast array of wildlife, and you'll reduce the strain on landfills. 

Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since July 2020.